OBJECTIVES: We are proceeding with our studies on the mechanism of action of adenylate cyclase. We have obtained additional proof that the enzyme oscillates between the inhibited phospho form and activated dephospho form. 2. We plan to study the action of phosphoglucomutase with various nonphosphorylated sugars in order to specify the enzyme requirements for the conformation of the molecule. 3. We plan to study the enzymes that are responsible for the breakdown of the tetrapeptide tuftsin. These are present in the cytosol fraction and in the lysosomes. BIBLIOGRAPHIC REFERENCES: Layne, P. P. and Najjar, V.A.: The Dephosphorylation of Phosphoglucomutase by Nucleophilic Reagents. J. Biol. Chem., 250, 966-972, 1975. Najjar, V.A.: Defective Phagocytosis Due to Deficiencies Involving the Tetrapeptide Tuftsin. The Journal of Pediatrics, 87, 1121-1124, 1975.